1. Field of the Invention
The present invention relates to a backplate, and more particularly to a backplate disposed on a backside of a printed circuit board for mounting a retention module disposed on the other side of the printed circuit board thereon. The backplate is featured with a robust coating thereon so as to provide durable insulative layer to prevent short circuiting of electrical components disposed on the printed circuit board.
2. Description of the Related Art
Center processing unit (CPU) sockets are mounted on motherboards and hold CPUs for execution of programs, and Intel Corp has designed and introduced a new CPU which is supported by a so-called LGA775 socket which is generally soldered onto a printed circuit board to support CPU and then makes electrical interconnections between the CPU and the printed circuit board.
During the operation of the CPU, a great deal of heat is generated and has to be dissipated efficiently and quickly during the operation of a computer device. In the past, a heatsink is introduced and includes a base plate with a plurality of fins extending therefrom. In use, the base plate of the heatsink is directly in contact with an upper surface of the CPU so as to dissipate the heat generated thereof. U.S. Pat. No. 6,061,239 issued to Blomquist on May 9, 2000 discloses a clip used to attach the heatsink to the CPU. The Blokquist clip is generally clipped onto the socket directly.
However, when the performance of the CPU becomes more and more powerful, the heatsink becomes larger and larger as well. Normally, the heatsink is about double to the dimension of the CPU. As a result, it is unlikely to have the clip engage with the socket.
When the 775 socket was introduced, the socket is provided with a stiffener, see also U.S. Pat. No. 7,001,197 issued to Shriai et al on Feb. 21, 2006, specially FIGS. 24A˜24B, and 25. Generally, the CPU is sandwiched between an element 508 and element 510. While FIG. 25 illustrates how a heatsink is used to dissipate the heat generated thereof.
U.S. Pat. No. 7,190,584 issued to Lee on Mar. 13, 2007 describes a typical retention module used to hold down a heatsink in close contact with the CPU, see FIGS. 5 and 6.
In order to properly support the retention module, a back plate element is introduced, see also U.S. Pat. No. 7,433,194 issued to Wu et al on Oct. 8, 2008. Element 8 in FIG. 2 is used to reinforce the retention module 30.
On the course of development, as disclosed in U.S. Pat. No. 7,217,149 issued to Ma on May 15, 2007, element 3, see FIG. 1 is bolted down to the printed circuit board or a reinforce backplate. Since both the element 3 and heatsink are both bolted onto the backplate, it becomes a vital part in computer device.
In general, the backplate is merely a metallic plate plated with a layer of zinc and nickel, and then covered with an insulative of layer so as to provide an insulative property thereon. The insulative layer will prevent the backplate from short-circuiting electrical components mounted on the backside of the printed circuit board.
The insulative layer could be a film adhered to one side of the metallic plate facing the underside of the printed circuit board. The film can be made from polyethylene terephthalate or polypropylene film with a thickness of one tenth of a centimeter. Since it has to be adhered to the metallic backplate with a strong adhesive, it has to properly and accurately cover all metallic surfaces facing the electronic components.
However, the insulative PET or PE film is not abrasive resistant. It may somehow get a cut or a scratch during the assembling process. This small defect may result an unwanted short-circuiting later on after a period of operation of the computer device. On the other hand, the insulative film is also easily peeled off therefrom, and creating even worse problems.
In view of the above, a new backplate for use with an electrical connector assembly which overcomes the above-mentioned disadvantages is desired.